Not trying be cute but I see you don't own a C-5 or a C-6 and you've probably used chips on your C-4's, which do work. No chips on C-5's or C-6's because everything is done by EFI controllers. Check out Chapter 10 in Will Handzel's book on Gen III tuning. I don't think there's a Callaway product mentioned in the whole book. When GM deveolped their C5-R and C6-R programs, they used what worked, no matter what the cost. What worked was headers, cams, head rework, etc-most everything was INTERNAL mods, not bolt ons. And, after everything was done, they still have to reflash the computer to get the motor to run properly.I say again, "anyone who says you gain on a HP on a C-6 using their plug wires and their new MAF is full of baloney"